Estimation of Sediment Yield from Forest Roads Using SEDMODL

Forest roads are constructed to access forest interior, wood extraction, conservation, afforestation and recreation. In forest road construction project, the trees and vegetation cover are removed and the soil structures are damaged. So, this causes to increase sediment production in forest roads. Increasing of the yield of sediment to river can damage water quality and aquatic ecosystem. Nowadays, there are different models for prediction of sediment yield and this can be helpful for researchers to predict amount of sediment production in forest roads. In this research, SEDMODL was used to estimate mean of annual production of sediment in forest roads. A road with a length of 2260 meter which is located in compartments of 26, 27 and 32 of Darabkola forests was selected. Then, the road length, road width, production rate of sediment with considering geology condition, road surface factor, traffic factor, longitudinal slope, rainfall and sediment delivery factor were calculated using GIS maps, forest management plan handbook and field survey. Results showed that the production rate of sediment in roads was 77.514 ton per year and of this value, 13.175 ton per year is imported to stream canals and rivers. Besides, the slope, distance of road to stream canals and cut slope height were the most important factors in sediment production and delivery to stream canals.